openwebf-app-devserver-network

Dev server reachability problems on real devices typically stem from incorrect host binding, firewall rules, or using localhost instead of LAN IP. Verify your dev server binds to 0.0.0.0 or your machine's LAN IP, confirm firewall permits inbound traffic on the server port, and ensure the device connects via LAN IP—not localhost. Check HMR websocket connectivity separately if hot module replacement fails.

Network connectivity failures occur when the dev server binds to localhost (127.0.0.1) instead of 0.0.0.0 or your LAN IP, or when firewall rules block the port. Use the --host flag in Vite or Webpack configuration to bind to 0.0.0.0, verify your device and dev machine are on the same network, and test the LAN IP directly from the device browser before debugging HMR.

HMR websocket configuration depends on your bundler. Vite and Webpack both require explicit HMR settings when the dev server binds to a non-localhost interface. Specify the HMR host and port in your bundler config to match your LAN IP and ensure websocket traffic reaches the device without firewall interference.

Allow inbound traffic on your dev server's port (typically 5173 for Vite, 8080 for Webpack) through your machine's firewall. Verify the port is not already in use, confirm your device can reach your machine's LAN IP on that port using basic connectivity tools, and check that any intermediate network appliances or VPN do not block the connection.

Confirm host binding by checking your Vite or Webpack dev server startup logs for the bound address. Use netstat or ss commands to verify the port listens on 0.0.0.0 or your target LAN IP. Test direct access from the device by visiting http://[your-lan-ip]:[port] in the device browser to isolate network versus configuration issues.

Localhost (127.0.0.1) is accessible only on the machine running the dev server, while LAN IP is reachable from other devices on the network. Real devices must connect via LAN IP. Configure your dev server to bind to 0.0.0.0 or explicitly set --host to your LAN IP so the device can establish both HTTP and HMR websocket connections.